1. Field of the Invention
The present invention relates to a modular drilling or workover rig substructure which may be transported to and from a rig site without entirely dismantling the substructure. In particular, the present invention is directed to a modular drilling rig substructure that may be transported to and from a rig site with various drill floor equipment and hand rails remaining in place and that minimizes liquid discharge by providing an integrated containment and drainage system.
2. Prior Art
A drilling rig substructure is one important component of a drilling or workover rig. Typically, a drilling rig substructure includes a raised platform or drilling floor which is above the level of a main deck or cellar deck and above the level of a well head, a blowout preventer and other equipment. An upstanding mast is connected to a floor of the rig and is often supported by the substructure. The mast may extend from 30 to 60 meters so that a substantial amount of weight is supported by the substructure.
The drilling rig substructure includes certain drilling floor equipment and supports personnel for various operations such as connecting and disconnecting pipe sections. Examples of equipment on the drilling floor include rotary tables, power tong apparatus, pipe handling systems, hydraulic winches, powered hoists and controls operated by personnel. Additionally, a V-door ramp may extend from the floor for movement of tubulars and equipment.
It is often necessary to move a drilling or workover rig, including all of its equipment, from one site to another. Traditionally, a rig substructure is assembled or rigged up by assembling the various component pieces of the substructure. For example, a framework is assembled and a plurality of floor panels are put in place to support the equipment and personnel on the drilling floor. While the floor panels are adequate for the purpose of support, they typically do not form a liquid-tight floor section. Accordingly, oil, liquids or debris may run off in the surrounding area. Increasingly, it is desirable to contain any such run-off.
Conversely, the drilling rig substructure is typically disassembled or rigged down by disassembling the various component pieces of the substructure. The various components are then transported to an alternate rig site and the entire process is again repeated.
In the past, various attempts have been made to place various equipment together in modular arrangements. For example, Bierscheid, Jr. (U.S. Pat. No. 4,899,832) discloses a modular drilling apparatus with a combined mast and drilling platform to facilitate assembly and disassembly of the drilling rig. Bierscheid, Jr. does not, however, provide a modular substructure.
It would be advantageous to provide a modular substructure apparatus and method wherein modular components could be moved to and from a rig site by trailer or other vehicle.
It would be advantageous to provide a modular substructure apparatus and process wherein various drill floor equipment and hand rails could remain in place during rig up, during rig down and during transportation operations.
It would also be desirable to provide a modular substructure apparatus and method to facilitate zero liquid discharge from the drill floor by providing an integrated substructure floor and drainage system.
It would be desirable to provide a modular substructure apparatus and method eliminating the requirement of a crane or a gin pole to assemble or rig up and to disassemble or rig down the substructure at a rig site.
It would be advantageous to provide a modular substructure apparatus and method wherein various structural, hydraulic and piping connections could be made at ground level prior to raising the drilling floor to its upstanding, use position.
It would be advantageous to provide a modular drilling rig substructure wherein component sections are joined by connectors not exposed to hook, rotary or set back live loads.
It would be advantageous to provide a modular drilling rig substructure having a drilling floor movable between a lowered, transportation position and an upstanding use position wherein the drilling floor remains parallel to a base at all times.